Rotary Machine and Internal Combustion Engine

ABSTRACT

The rotary displacement device has a rotating piston and a rotating housing that has a fixed vane. The cylindrical rotor is eccentrically placed in relation to its cylindrical housing. The gas and air flow goes through the hollow-centered shaft via channels in the rotor. The sealing grid in the displacement space is improved to minimize the friction and thereby gain power and better efficiency.

THE ROTARY MACHINE

The present invention refers to rotary displacement devices withrotating pistons like used in compressors, blowers, air engines androtary internal combustion engines. This invention is such a device thatcan be used in the mentioned applications, particularly rotary internalcombustion engines, which in the last mentioned application can becompounded of two or more devises according to the present invention ofwhich at least one has the function as a compressor and the other or,whenever applicable, the others has the function of a power unit orexpander or expanders, that is to transfer heat energy to kineticenergy. The units work together so the fluid can pass from one to theother. A transmission ensures the housings to rotate.

On the market there are a great number of rotary devices of variousprinciples, one of each with its special advantages and disadvantages.As rotary displacement engine the Wankel engine is one of the most knownand the most developed of all.

THE OBJECT OF THE INVENTION

Concerning compressors it is only the traditional piston compressorwhich have the best efficiency compared to other designs, because of theeffective sealing arrangement of piston rings. Many rotary designs havefailed because of sealing problems. Complex geometries prevent a simplesealing arrangement. For instance it is well known that the Wankelengine has gone through many difficulties to solve their sealingproblem. However rotary designs have other advantages as smooth running,light design, and low friction. The present invention also facilitates asimple device. It is an object of the invention to combine the bestfeatures of most compressor designs for a wide application. In order toaccomplish that, it is therefore an object of the invention to improvethe sealing grid in the displacement space and to minimise the frictionand thereby gain power and better efficiency. Another object of theinvention is, in the application of a rotary combustion engine, tocreate a simple device with a large possibility of development towardsbetter environment qualities, especially use of hydrogen.

In the use of conventional and other alternative fuels the aim is todevelop higher efficiency with preserving the great application area ofthe conventional piston engine.

Inner and Outer Rotor Design

The invention has a cylindrical rotor eccentrically placed in relationto its cylindrical housing characterised in that the mentioned housingalso is rotating. The mentioned inner rotor is resting and rolling onthe inner wall of the outer housing (contact line) and makes to rotateby a vane fixed on the housing. It is that mentioned housing because ofthe fixed vane that receive, alternatively in the case of an engineapplication, give the driving power. The inner rotor is thereby notburdened with any other torque than its own friction. The gas and airflow goes through the hollow-centred shaft via channels in the rotor.That makes the housing be designed without openings or ports for thementioned flow. The co-rotation reduces the friction substantially.

Displacement Variation

The eccentrically mounted rotor forms a variable volume betweenfollowing surfaces besides lateral walls: 1) the inner surface of thehousing, 2) the vane and 3) the outer surface of the rotor. This spacehas of obvious reasons its largest cross-sectional area diametricopposite the contact line between the rotor and its housing. That causesthe volume within mentioned surfaces to change in relation to the vaneapproaching or removing the contact line. That feature is particularlyuseful in the mentioned combustion engine, where one or more compressorunits and power or expander unit/s can be joined together so itparadoxically creates compression in an expanding volume in thecombustion chamber. That is beneficial in the endeavour to approach anisothermal (constant temperature) compression. That can be accomplishedby intercooler/s between the units. It explains in detail below. It isalso simple to turn the revolving direction of a compressor design foran application as an expander for converting a fluid pressure to arotating movement, for instance compressed air, or a fluid from anexternal combustion.

Sealing

As the vane 4 is fixed between the lateral walls and towards the housingthere is no need of an apex seal or side seals as in the Wankel engine.The rings and the grooves may be designed with a cross cut angel ofaround 45 degrees in order to seal properly in the corner, that is bothagainst the lateral walls and as close as possible against the innersurface of the housing 1 (contact line).

Cooling

The outer rotor has peripheral fins for efficient cooling duringrotation.

The central parts of the rotor together with the common shaft and theend of the vane facing the centre of the rotor are in open contact withthe open air, which by the fan action caused by the rotation contributesto cool the machine. The vane itself has also air channels for cooling.The gas flow is adjusted by valves.

The Internal Combustion Engine.

During the years many alternative combustion engines have appeared toeliminate the disadvantages that conventional reciprocating pistonengines are afflicted with. The gas turbine, the Stirling engine and theWankel engine are some examples of alternative engines being researchedupon and still are being invested money on. But these engines havelimited application areas where their special advantages can beutilised. The environmental demands are given gradually largerimportance and many have stumbled and failed because of other problems,why the reciprocating piston engines still are the dominating engines inthe market.

Concerning the application as a rotary internal combustion engine theaim is to make a better combustion process and to facilitate the use ofalternative fuels, for instance hydrogen. Furthermore the aim is toessentially increase the efficiency, which indirect affects theenvironment by lower fuel consumption and lower pollution.

Disadvantages of the Reciprocating Piston Engine.

1. Single Volume Process

In contemporary piston engines all the four strokes: intake,compression, combustion and exhaust, take place in one single volume. Itcan be regarded as preferable to share the strokes with more volumes inorder to achieve best efficiency.

2. Crank Gear

The crank gear of the piston engine and thereby the connected pistonmotion and the inertia of the reciprocating pistons have in severaldecades been object to brain efforts of inventors and scientists forbetter solutions. Therefore many suggestions to rotary engines haveappeared since many years back.

3. Efficiency

Another area, which constantly is developing is the efforts to increasethe efficiency. According to the thermodynamics the Carnot-process hasthe highest theoretical thermal efficiency. Rudolph Diesel tried in histime to make his engine to work according to that process in a largeextent as possible. But it is difficult to apply that process on commonengines. It has also a long time been known, that the efficiency andthereby the fuel consumption, is largely connected to the compressionratio. The development has therefore gone towards manufacturing engineswith still higher compression ratio. But the limiting factor has beenfuel qualities and, concerning diesel engines, the high combustionpressures, which demand heavy designs. Despite the high top pressuresseems to be an important parameter for a high efficiency, it has ondifferent ways been an endeavour to level those peak pressures towards ahigher mean pressure. But it is difficult to accomplish that in thetraditional piston engine.

4. Compression Rate

A combustion engine, and then especially the Otto engine, has itsoptimal efficiency at a given speed and load. At part load theefficiency is decreasing because of the inlet pressure is decreasing bythrottling. That lowers in turn that compression pressure, which givesthe best efficiency. Therefore it has been regarded desirable to varythe compression ratio at different load. The proposed engine accordingto the present invention solves that problem in an easy way.

Another problem is the high compression temperature that arises whenstriving after higher compression ratio. That increases the compressionload and gives higher N0x pollution. Therefore it has been tried withdifferent system of intercoolers.

5. Energy of Exhaust Gases

The exhaust gases in the common piston engine have, when they leave theengine, still a large content of energy. An Englishman, James Atkinson,introduced in the end of the 1800^(th) century a piston engine with acomplicated crankshaft, which extended the expansion stroke in order toutilize that content of energy. It was then observed that those engineshad a higher efficiency than comparable engines at that time. As thecrankshaft became clumsy, it was tried in the following generations ofengines to approach the Atkinson cycle by controlling the compressionand expansion intervals via opening and closing of the valves, whichhowever do not give the same result as in the “genuine” Atkinson engine.

6. Scavenging

The scavenging of the exhaust gases in the space between the piston attop dead center, TDC and the cylinder head is another area which hasresulted in comprehensive efforts of improvements. Full scavenging canhardly be achieved in a traditional piston engine, as the exhaust valvecloses at TDC and it remains burnt gases in the mentioned space.

7. Moment Arm

The length of the moment arm affects the torque. The longer arm thegreater torque. The force line of action is almost perpendicular to theaxis of rotation at TDC and some degrees of rotation thereafter. Thatmakes the moment arm very small, and then when most of the energy isgenerated. Much of the power is therefore wasted,

8. Valves

Filling and exhaust require valves and contemporary piston engines havetwo or more valves in each cylinder. That makes the engine more complexand expensive.

Solutions.

1. Single Volume Process

The present invention is very useful for alternative applications. Asthe machine can work as compressor, air engine or expander, it ispossible to combine two or more machines for the very best efficiency.This description shows only two solutions, one proposal with twomachines and another with three machines.

2. Crank Gear

The present invention is designed as a rotary and hence a traditionalcrank gear is not needed. It solves mentioned problems and are ascombustion engine built according to the so-called Brayton principle,that is an engine with two units where intake and compression are donein one unit and expansion and exhaust are done in the other. Anotherproposal shows, as mentioned above, three machines: two compressors andone power unit (expander). The rotary principle makes it possible toavoid the inertia of the crank gear and therefore facilitate a higherspeed.

3. Efficiency

In the case of three machines, the Carnot-process can be approached,which is the process with the highest efficiency. The compression isdone more or less isothermal in the first compressor with anintercooler, and step two in the second compressor (adiabatic) where thecompression is done isentropic, when a valve is opened in the expanderunit, where compression continues to a certain level. Then the valvecloses and the gas ignites. When the vane in the expander moves from thecontact line and forward, the volume in the compression/combustionchamber thus changes from zero to the desirable volume. Despite of spaceincrement the pressure in the expanding volume can be kept constant oreven a pressure increment can take place. This seems to be a paradox,but depends of the open connection with the compressor in the momentwhen the valve is open and the space decrease in the compressor islarger than the compression/combustion chamber increment in theexpander. This lowers the compression heat and thus minimizes the NO xemissions and increases the efficiency.

4. Compression Rate

The compression rate is variable during the engine run by a device,which affects the opening and closing times of the intake valve viaexternal influence. That is an advantage for varied load conditions.

The process has no turning fluids as in the reciprocating engine but itresembles more the process of a gas turbine. That can make thecompression ratio be higher than contemporary engines and the combustionpressure more leveled.

5. Energy of Exhaust Gases

The present invention makes it easier to achieve beneficial parametersin that the size relation between the units, compressor/s and expander,can mutually be chosen freely depending on desired application. Forinstance the expander can have a larger expansion rate than thecompression rate in the compressor. All the energy of the fluid cantherefore be utilized.

6. Scavenging

The exhaust volume in the expander goes during every revolution towardszero volume, when the vane moves up to the contact line. Thisarrangement is an advantage for gas exchange. There will be no mixtureof fresh and burnt gases. The intake valve has no connection with theexhaust port and the design is therefore secure from an undesirableignition. This would be an advantage for use of hydrogen.

7. Moment Arm

The invention has no crank gear but a fixed vane with a moment arm ofconstant length that transfers the power to a revolving motion withoutlosses.

8. Valves

Only one valve is needed for opening and closing the intake fluid. Theexhaust channel is constant open.

Several designs within the wide area of the present invention would bepossible. Concerning combustion engines is here below, for the sake ofsimplicity, only described two alternatives: alt 1; one compressor withan intercooler+one expander connected with each other via a commonhollow-centred shaft, FIG. 12, and alt 2; one compressor, named “K1”with an intercooler+another compressor, named “K2”+one expander,connected with each other in the same way, schematically shown, FIG. 16.

DESCRIPTION OF THE DRAWINGS

FIG. 1. shows a rotary machine, for instance a compressor, in enlargedsection view along the line A-A in FIG. 2.

FIG. 2. shows the same machine from intake front.

FIG. 3. shows the same machine in perspective view.

FIG. 4. shows the same machine in section view along the line B-B inFIG. 5.

FIG. 5 shows the same machine in a side view.

FIG. 6 shows a rotary machine designed as an expander in a combustionengine in section view along the line C-C in FIG. 7, displaying thevalve mechanism.

FIG. 7 shows the same expander in a side view.

FIG. 8 shows the same machine in section view along the line D-D in FIG.9, disclosing the exhaust channel and an ignition devise (here a sparkplug).

FIG. 9 shows the same machine in side view as in FIG. 7.

FIG. 10 shows the same machine in section view along the line E-E inFIG. 11, disclosing part of the mechanism of opening and closing thevalve (12 and 13).

FIG. 11 shows the same machine in a side view as in FIG. 7 and FIG. 9.

FIG. 11 a shows an expander in section view along the line F-F in FIG.11 b.

FIG. 11 b shows the same machine in front view.

FIG. 12 shows an engine with compressor, intercooler and expanderconnected to each other.

FIG. 13 shows a rotor in perspective view displaying the sealingarrangement and the abutment halves for the vane.

FIG. 14 a) shows an expander rotor in perspective view with an exampleof valve arrangement mounted and b) shows the rotor in exploded viewdisclosing the valve mechanism.

FIG. 15 shows the valve lifter and adjustable cam 13: a) in explodedview, b) the cam in upper position, and c) in lower position.

FIG. 16. Shows a schematic view of an isothermal compressor (K1) with anintercooler and an adiabatic compressor K2 and an expander connected toeach other.

FIG. 17-21. Shows schematic views of the fluid in different positions ofa revolution.

FIG. 22. Shows a diagram with volume and pressure curves. It serves onlyto roughly enlighten the process of a combustion engine according to thepresent invention and not to be regarded as a final analysis.

WORKING DESCRIPTION FOR A ROTARY MACHINE

The machine consists of a rotor 2, which is eccentrically placed in ahousing 1 with contact against said housing 1 (the contact line 2 a) andwhich rotor 2 has a diameter less than said housing, so it therebycreates a space between the outer circumference of the rotor 2 and theinner circumference of the housing 1. By that eccentric arrangement thementioned space has its largest section surface diametrical opposite thecontact line 2 a. On the inner circumference surface of the housing 1there is a vane 4, which object is to create, together with thesurrounding surfaces of the rotor 2 and housing 1, variable volumes.Another object of said vane is to bring the rotor 2 to rotate by arecess in the mentioned rotor made for said vane. The housing 1 androtor 2 are each of them hanged in a bearing arrangement mounted on thebase 14. The rotor 2 is not burdened with any torque except that causedby friction. A transmission 9 a transmit power to and alternatively from(depending on application) an axis 9 b for external apparatus. The rotor2 has intake and outlet channels 6, which each of them and independentof each other lead via other connected channels 5 to openings on eachside of the vane 4 on the outer surface of the rotor 2. The rotor 2 hason each side axial recesses 5 a, which purpose is for balancing and forevacuating of heat via holes 9 out to the open air. As compressor thereis a back-pressure valve 17 mounted, FIG. 20. The vane 4 is surroundedby two abutments halves 8 in the rotor slot. They receive an oscillatingmovement from the vane 4 in relation to the rotor 2. The sealingarrangement 16, FIG. 13, consist of one ring on each side of the rotor 2fitted in grooves. The rings and the grooves may be designed with across cut angel in a section view of around 45 degrees in order to sealproperly partly against the lateral walls and partly as close aspossible against the inner surface of the housing 1.

Working Description as Combustion Engine.

As combustion engine the invention can be designed with one or morecompressors and one or more expanders connected to each other. Thisdescription deals in the first alternative only with one compressor andone expander, FIG. 12. In the compressor take inlet and compressionplace and in the expander compression, combustion and exhaust. In thesecond alternative there is another compressor K2 connected,schematically shown in FIGS. 17-21. Between the units there is possibleto connect an intercooler 18 for reducing the compression heat. Theexpander unit has, besides mentioned design above, also an intake valve7 and ignition arrangement 10, FIG. 6 respective FIG. 8. An example ofvalve arrangement shows in FIG. 14 and FIG. 15. The valve lifter arm 11has a roller 12, which, when rolling on the adjustable cam 13, transferpower, via the arm 11 to the valve 7, which then opens.

Compressor and expander are in this example of application so connectedto each other that when the vane 4 in the compressor has rotated andcreated a volume decrease and thereby a certain pressure, the valve 7opens by the adjustable cam 13 affected by an external device (hereexemplified by a simple handle 15). The flow continues into thecombustion volume in the expander, where ignition and combustion occurand the working phase starts.

The process starts with inlet of air or gas into the compressor, FIG.12, through the channels 6 in the hollow-centered shaft. Rotor channels5 on each side of the vane 4 emerge into the corresponding volume aheadof, respective after the vane 4. From the compressor the compressedfluid leads via an intercooler 18, in the first mentioned alternative tothe expander, and in the second alternative to another compressor K2 forfurther compression into the expander.

The second alternative are more described in detail as follows.

The aim with two compressors is to approach the Carnot cycle, which iswell known in the thermodynamics world for having the best theoreticalthermal efficiency. The first compression phase is there recorded asisothermal, that is to say the warmth generated is rejected to the openair by a cooling arrangement. The following phase is isentropic(adiabatic) compression. The heat generated is now preserved in as alarge extent as possible before combustion. That is not possible toaccomplish in contemporary piston engine, where all the phases occur inone volume. Therefore the present invention disclose a solution with twocompressors. The first compressor K1, FIGS. 16-21, has large coolingsurfaces and combined with an intercooler 18 rejects all the heatgenerated to the environment (isothermal phase). The second compressorK2 has a smaller volume compared to K1 so the volume relation betweenthe two is determined to an optimal rate for best efficiency. K2receives the precompressed fluid from K1 (curve a in FIG. 22) andcontinues the compression into the expander to the desirable level.

See FIGS. 17-22. In the compressor K1 has intake and compression phasesstarted a new revolution. In the expander is the working phase stillgoing. The three units has reached the position in FIG. 17 and diagramFIG. 22. The valve 7 in the expander is closed. Notice in the figure thevalve 7 is sketched with en open flap in order to mark an interruptedfluid into the expander).

In position FIG. 18 the pressure, curve b, has reached the level shownin diagram FIG. 22. The valve 7 has just opened in the expander andcompression continues simultaneously in K2 and the expander up toposition in FIG. 19, where the fluid is interrupted by the closing valveand combustion starts. The curve for the fluid pressure is slopingupwards from around 180 degrees to around 240 degrees (0 to around 80 inthe expander) of a revolution indicating a pressure increase in theexpander. By following the curves for volume alteration it is evident tosee that the volume decrease is larger in the compressor/s than thevolume increase in the expander. Hence the pressure increases.

There is a channel 19 in the rotor K2, which opens when the expandervalve 7 has closed and lets the fluid pass over into the intake volume,FIG. 20. In position FIG. 21 a new revolution starts. A back valve 17prevents the remaining fluid pressure in the intercooler to flow backinto K1 but flows instead into K2. The intake pressure K2 increasesagain around position in FIG. 18.

1. A rotary displacement machine for evacuating or compressing a fluidor alternatively converting a fluid pressure to a rotating movementcomprising: a cylindrical housing and a rotor eccentrically disposed inrelation to said housing generating a contact line, the housing a vaneand lateral walls being fixed together and thereby generating a rotatingunit surrounding the rotor.
 2. The rotary machine according to claim 1,wherein the rotor shaft is hollow centered generating channels for in-and outlet of the fluid.
 3. The rotary machine according to claim 1wherein the rotating unit via a transmission transmits or alternativelyreceives power by the fluid pressure affecting the vane respectivelybeing affected by the vane.
 4. The rotary machine according to claim 1wherein each of two parallel and annular sides of sealing rings is, atan imagined extension towards a circle center of the rings, generating acone and a third side of the rings is tightening against lateral walls.5. The rotary machine according to claim 1 wherein the rotary machine isa combustion engine that has a fluid being compressed in ansimultaneously expanding combustion chamber before ignition.
 6. Therotary machine according to claim 5 wherein the combustion engine has afluid that is being cooled during the compression phase in ansimultaneously expanding combustion camber before ignition.
 7. Therotary machine according to claim 1 wherein the rotary machine has avalve (7) that has variable opening and closing times in order togenerate a variable compression rate.